Special Testing Procedures
Special Testing ProceduresEngine Idle Speed Check
Refer to Computers and Control Systems for diagnosis and testing of the engine idle speed.
Line Pressure Test
CAUTION: Carry out Line Pressure Test prior to carrying out Stall Speed Test. If line pressure is low at stall, do not carry out the Stall Speed Test or further transmission damage will occur. Do not maintain wide open throttle in any gear range for more than 5 seconds.
NOTE: Certain sensor failures may cause high PC, FMEM (Failure Mode Effect Management) actions. Be sure that self test and electrical repairs have been carried out or test results may be incorrect.
NOTE: The line pressure tap is used to verify output pressure from PC A or PC B by turning either one off while verifying the output from the other solenoid. The 2nd pressure tap is used to verify the output from the PC C solenoid.
This test verifies that the line pressure is within specifications.
1. Connect the pressure gauge to the line pressure tap.
2. Start the engine and check the line pressures. Refer to the following Line Pressure Chart for the correct specification.
Line Pressure Chart
3. If the line pressure is not within specifications, check the PC C pressure.
4. Connect the pressure gauge to the PC C pressure tap.
5. Start the engine and check the PC C pressure. Refer to Line Pressure Diagnosis Chart for the correct specification.
6. If the PC C pressure is not within specification, Go to Pinpoint Test D to diagnose PC C operation. If PC C operation is OK, refer to Line Pressure Diagnosis Chart for line pressure concern causes. Test D: Pressure Control (PC) Solenoids (PCA, PCB, PCC)
Line Pressure Diagnosis Chart
Stall Speed Test
This test checks operation of the following items:
^ Torque converter clutch
^ Forward clutch
^ Low-one way clutch (OWC) assembly
^ Engine driveability concerns
^ Overdrive one-way clutch assembly
WARNING: Apply the parking brake firmly while carrying out each Stall Speed Test.
CAUTION: Always carry out the Line Pressure Test procedures prior to carrying out the Stall Speed Test. If line pressure is low at stall, do not carry out the Stall Speed Test or further transmission damage will occur.
NOTE: The Stall Speed Test should be carried out with the engine and transmission at normal operating temperatures.
1. Connect tachometer to the engine.
2. CAUTION: After testing each of the following ranges (D), D, 3, 2, 1 and R. move the transmission range selector lever to N (NEUTRAL) and run the engine at 1,000 rpm for about 15 seconds to allow the torque converter to cool before testing the next range.
CAUTION: Do not maintain wide open throttle in any range for more than 5 seconds.
CAUTION: If the engine rpm recorded by the tachometer exceeds maximum specified rpm, release the accelerator pedal immediately. Clutch or band slippage is indicated.
NOTE: Prolonged use of this procedure may set Diagnostic Trouble Code P0712 or P1783. After carrying out Stall Speed Test, run OBD Test and clear DTC's from memory.
Press the accelerator pedal to floor (WOT) in each range. Record rpm reached in each range. Stall speeds should be as follows:
Stall Speed Chart
If stall speeds were too high, refer to the following Stall Speed Diagnosis Chart. If stall speeds were too low, 1st check the engine idle speed. If engine idle is OK, remove torque converter and check the torque converter one-way clutch for slippage.
Part 1:
Part 2:
Stall Speed Diagnosis Chart
Air Pressure Tests
A no-drive or erratic shift condition may be due to inoperative bands and clutches. To diagnose these conditions a series of checks can be made by substituting air pressure for fluid to determine the location of the damaged or obstructed component.
Follow the procedure to determine the location of the inoperative clutch or band by substituting air pressure into the various test plate passages.
NOTE: Use only dry, regulated air pressure, 276 kPa (40 psi) maximum.
1. Remove the main control valve body.
2. Install the transmission test plate and gasket. Tighten bolts to 10 Nm (89 inch lbs.).
3. NOTE: Do not apply air to the test plate vent hole.
Apply air to the appropriate clutch or servo port (refer to plate layout diagram). Refer to the Air Pressure Test Diagnostic Chart for conditions, possible causes and actions.
4. After the testing is completed, remove the air test plate and gasket and proceed with any repairs that are needed.
5. After the repairs are completed, install the main control valve body.
Part 1:
Part 2:
Air Pressure Test Diagnostic Chart